Mike Enslin is a cynical author who debunks haunted locations. He receives an anonymous postcard warning him not to enter Room 1408 at the Dolphin Hotel in New York. Intrigued and skeptical, he insists on staying in the room despite the hotel manager's warnings.

What follows is a terrifying psychological descent as Enslin becomes trapped in Room 1408, where time, space, and his mind begin to unravel. The room manifests his deepest fears and grief, particularly surrounding the death of his daughter. The horror is not in jump scares, but in the slow psychological torment that leaves him questioning reality.